[[quoteright:350:[[Disney/{{Tangled}} http://static.tvtropes.org/pmwiki/pub/images/RapunzelMoodSwing_3762.jpg]]]]
[[caption-width-right:350:[[AccidentalPun Hehe, "swing".]]]]

->''"You know, I can't help but notice you seem a little at war with yourself here."''
-->--'''[[{{Disney/Tangled}} Flynn Rider,]]''' in response to the page image

A character whose personality isn't marked by any set mood, but by their tendency to swing between moods drastically. Sometimes (if the characters around them are lucky) there's some sort of warning of an impending mood swing -- or at least a recognizable cause -- but there may just as easily be no warning whatsoever.

Frequently this is combined with [[http://en.wikipedia.org/wiki/Emotional_lability emotional lability]], so they skip any emotion that isn't ''extreme''. They're never just happy, they're the cheeriest GenkiGirl in the world. They're never just sad; they're [[DrivenToSuicide on the verge of suicide]]. They're never just angry; they're filled with UnstoppableRage. And they can flip between any of them at a moment's notice. May very well be a one-person FourTemperamentEnsemble.

Though they may be referred to as "bipolar", their mood swings are generally much more abrupt and frequent than the periods of mania or depression associated with type I of real-life [[http://en.wikipedia.org/wiki/Bipolar_disorder bipolar disorder.]] This can, however, be a facet of type II bipolar disorder or [[http://en.wikipedia.org/wiki/Borderline_personality_disorder borderline personality disorder]].

This is a stereotypical trait of women who are currently [[AllPeriodsArePMS menstruating or suffering from PMS]]. It is TruthInTelevision, and fairly common at that, but not typically as extreme as fiction portrays it to be nor as universal. Also, not every woman whose mood is affected by menstrual hormones will be susceptible to every mood; some get stuck swinging into ''one'' mood and temporarily become a FragileFlower or acquire a HairTriggerTemper. Since the same hormones are involved, pregnant women are also known for being {{Mood Swinger}}s.

The Mood Swinger as a LoveInterest frequently fills the role of the {{Tsundere}}. This is also a common trait of TheCaligula.

For even more extreme cases, see HairTriggerTemper, SplitPersonality, JekyllAndHyde, {{Tsundere}} and {{Yandere}}. Not to be confused with MoodWhiplash, which is a trait of the ''storytelling'', not an individual character.
----
!!Examples

[[foldercontrol]]

[[folder:Anime and Manga]]
* Alois Trancy of ''Manga/BlackButler''. Throughout the first episode he switches from cute and innocent to AxCrazy so many times it could make someone dizzy.
** A rather dark example, since Alois's mood swings tend to be severe MoodWhiplash as well - going from cute and entertaining to TroublingUnchildlikeBehavior with ridiculous speed, and then back again. Not to mention that his extremes can create gems like the time he stopped innocently eating breakfast to [[EyeScream gauge his fingers through a maid's eye]] and then wiped his hand and went back to his eggs.
* Revy of ''Manga/BlackLagoon'' normally displays a wide range of emotions, all the way from affection to psychotic rage to calm boredom.
* Kagura from ''FruitsBasket''. She seems cute at first, but whenever Kyo's around she becomes a combination of a {{Yandere}} and a {{Tsundere}}.
** In the beginning at least, Kyo came across as this since he had NoSocialSkills and had a tendency to snap at people he wasn't mad at. So he'd yell at someone, apologize, then yell at them for not understanding him. Then apologize...
* ''{{Gundam 00}}'': Allelujah in the movie, leaving some questions to how the SplitPersonality thing is going since hes OutOfFocus
* ''LightNovel/HaruhiSuzumiya'' comes close. Now she's a cheerful GenkiGirl, the next scene she's [[{{Jerkass}} abrasive, confrontational, dominant and almost narcissistic,]] after that she may become extremely [[TheEeyore melancholic]]. There are reasons for her mood-changes, but sometimes it just appears randomly.
* Rena from ''VisualNovel/HigurashiNoNakuKoroNi''. This and the fact that she's a NightmareFetishist seems innocent enough at first, but then you find out she's a GrotesqueCute {{Yandere}} antagonist best known as the "Cleaver Girl" for her AxCrazy tendencies. [[spoiler:[[GroundhogDayLoop Sometimes]]]]. The games hint she has a bipolar disorder, but it's exaggerated so it [[RuleOfScary seems freakier]].
* [[PhysicalGod Misao Mikogami]] from ''Kami Kaze'' can be a [[GenkiGirl fairly cheerful and fun-loving]] teenage girl, [[TheParagon nice to anyone who needs a hand]], and will stand up for someone when they need it. Say the wrong thing around her and [[HairTriggerTemper her mood will change so fast]] that you won't even have the time to mouth the words OhCrap before you're standing under an ocean of water with your current surroundings gone so far beyond the GodzillaThreshold that you'll be glad you're not around [[ApocalypseHow to see the aftermath]]. [[FromBadToWorse And that's not counting the times]] you've [[UnstoppableRage pissed her off enough]] that she decides [[FateWorseThanDeath to play around with you for a little while]]. She's the ''nicest'' deity [[CrapsackWorld in this series]].[[note]]The nastiest go straight through the MoralEventHorizon on [[ButForMeItWasTuesday your average Tuesday]] and don't even look back [[CrossesTheLineTwice to see where the line went]][[/note]].
* Ayukawa Madoka from ''KimagureOrangeRoad'' is pretty bad about this, though her swings are more day to day than moment to moment. And of course she's the Tsundere leg of the Love Triangle.
* Yuno of ''MiraiNikki'' often can go from a [[{{Moe}} sweet, lovable and huggable darling]] to [[AxCrazy a murderous and terrifying psychopath]] on a whim[[note]]or even ''both''[[/note]], and usually [[MoodWhiplash in the span of a single episode]]. Most of the time, all it takes is either [[ViolentlyProtectiveGirlfriend threatening]] or [[ClingyJealousGirl flirting with]] Yukiteru.
* Karin from ''Manga/{{Naruto}}''. Karin has a fluctuating personality, at times appearing stern and tough and {{Tsundere}} and other times appearing carefree and highly flirtatious, but only around Sasuke.
** She even uses it as a way to escape some guards in Konoha.
** Jugo has it even worse from a GentleGiant to AxCrazy. He even been named [[RedBaron Jugo "of The Scales"]].
* [[TheCaligula King Hamdo]] from ''NowAndThenHereAndThere'' takes this trope to terrifying extents. His moods usually switch from petty, to cruel, to violently moody, to pathetic, and back, usually over the course of a few minutes.
* Harry of ''OutlawStar''.
* A good deal of the characters from ''SayonaraZetsubouSensei''. Namely Kafuka who's somewhat similar to Rena, except she's even more overly optimistic.
* Kamille in ''ZetaGundam'' can go from personable and friendly to teenage angst-fest in the blink of an eye (NotHyperbole). It's oftentimes difficult to tell what exactly set him off.
* Naomi in ''ZettaiKarenChildren'' started off being the calm, sweet girl all the time. Once she realized that her [[DirtyOldMan supervisor Tanizaki's]] [[WifeHusbandry treatment]] of her was why she was having trouble with her powers, she lets loose and from then on shows no restraint in throwing him into a wall when he gets too close. Her CodeName even changes from "Kitty Cat" to "Wild Cat" in the process.
* ACDC from ''Manga/JojosBizarreAdventure'', even admitting that he's the most emotional of the Pillar Men. When Joseph [[spoiler: cuts off his arm and destroys it so he can't reattach it]], his reaction is to...[[InelegantBlubbering burst into tears and cry like a little girl]], and then after a while stop as quickly as he started and claim he was just blowing off steam. This actually makes him dangerous; Joseph reads his opponents to get the upper hand on them, but it's impossible to read ACDC's constant mood shifts.
* ''Manga/{{Upotte}}'': Agu (a personification of the Steyr AUG) switches from a shy assault rifle to an overbearing squad automatic weapon with a change of barrel/hairstyle.
* ''Manga/MagicalRecordLyricalNanohaForce'' has Curren Hückbein and Cypha. Cypha is TheStoic, but she often switch to her sadistic AxCrazy persona when she's in a battle. The BigBad Curren can be very childish, acts as cute and sweet woman, only to switch to her dark, intimidating and creepy persona, then back and forth.
[[/folder]]

[[folder:Fan Fic]]
* ''Fanfic/CalvinAndHobbesIIIDoubleTrouble'' gives us the [[ExactlyWhatItSaysOnTheTin Mood Swing Babbler]], an alien from [[APlanetNamedZok Planet Zok]]
* [[HomeStuck Sollux]] is this in canon, but [[UpToEleven even more so]] in the fanadventure ''Webcomic/BeTheSeaDwellerLowblood''. He and Karkat will get in a fight, one of them will apologize, the other won't accept, then the second one apologizes and the first one ignores him, they get into another fight, one of them will apologize but be rejected ''again'', one will think about apologizing but change his mind, one will beat himself up over not apologizing sooner but then not go through with it, etc, etc, etc.
-->Congratulations. Over the span of two minutes, you succeed in getting pissed at Karkat, forgiving him, and getting pissed at him again, despite the fact that you have neither spoken to him nor physically seen him for hours.
-->This is not bipolarity. Bipolarity is a pendulum swinging back and forth, going tick-tock like the beat of a heart, sometimes slowing so that it will be days before the next tick, perigees before the next tock. Sometimes for a time, it freezes in the middle, and you can breathe easy and clear your head. The emotions are not nearly as neat and tidy as a pendulum, but the process, the process is.
-->This is not bipolarity.
-->This is insanity. Not the tick-tock of a pendulum but the tacktacktack of a pinball machine. The swings are jagged and irregular, not back and forth but lurching all over creation. You're lucky when you get to hold on to an emotion for more than a fleeting moment.
-->You haven't been "bipolar" in sweeps. You miss being bipolar. It was better than this unidentifiable monstrosity.
-->No it wasn't! Ha ha ha, what are you talking about? It was even MORE horrible compared to this! At least this way you're guaranteed to not have to put up with a bad mood very long.
-->... Except that you usually switch from one bad mood to another bad mood.
* In ''FanFic/MegaManReawakened'', Tron Bonne has been like this since Arc 5 began--and it's revealed it's because [[spoiler:she's pregnant]].
[[/folder]]

[[folder:Film - Animated]]
* Boingo from ''{{Hoodwinked}}'' acts like this once he drops his TastesLikeDiabetes facade and starts acting like a supervillain. The commentary remarks that on one occasion they couldn't decide which take to use (maniacal, verge of tears, etc), so they just decided to string them all together to very good effect.
* After escaping from the tower in which she's lived her whole life without leaving in ''{{Disney/Tangled}}'', Rapunzel swerves wildly between unrestrained joy at being liberated and crushing guilt at breaking the promise she made to Mother Gothel to never leave the tower.
-->[ecstatic] I can't ''believe'' I ''did this!''\\
[horrified] [-I can't believe I did this.-]\\
[overjoyed] ''I can't '''believe''' I '''did this!''' ''\\
[appalled] Mother would be so furious.\\
[sitting by pond] But that's okay, I mean, what she doesn't know who't ''kill'' her, right?\\
[sitting in cave] Oh my gosh. This would ''kill'' her!\\
[running through leaves] '''This is sooo funnnn!!'''\\
[[[WallBang leaning on tree]]] I am a horrible daughter. I'm going back!\\
[rolling down hill] '''I am ''never going back!'''''\\
[facedown in meadow] I am a ''despicable human being''.\\
[swinging from tree] '''WOO-HOOOO!! Best! Day! Ever!'''\\
[sitting by rock] *sobbing*
* The song [[http://www.youtube.com/watch?v=moSFlvxnbgk Let It Go]] in ''{{Disney/Frozen}}'' is emotionally deep and complicated, and during some of its most intricate moments [[http://www.naclhv.com/2014/02/elsas-facial-expressions-during-let-it.html Elsa wears many highly expressive faces]] that change nearly second by second.
* Basil from ''Disney/TheGreatMouseDetective'' certainly swings from manically happy to crushingly depressed and back to manically happy again quickly. Of course, this is because he's based on SherlockHolmes, who was possibly bipolar, and definitely a massive cocaine addict. So either Basil could use a little lithium, or he's gotten into a bad, mouse-sized vial of seven per cent solution (an expected hazard of living under Holmes' floor).
* ''WesternAnimation/TheNightmareBeforeChristmas'': Jack Skellington, particularly during his BSODSong, "Poor Jack".
** The Mayor of Halloweentown, to the point of literally having 2 different faces.
* ''Disney/WreckItRalph'': King Candy is known to switch emotions wildly several times within the same sentence - from cheerful giggling, to flustered, to angry, to some more giggling. He can be making puns one second and furiously ordering around his guards in the next. [[spoiler:Even when he briefly drops the King Candy image and shows himself as Turbo, he can't help but snap to gleeful conceit in-between his fury at his plans being unraveled.]]
[[/folder]]

[[folder:Film - LiveAction]]
* Paul, later in ''Film/PainAndGain'', due the effects of cocaine (as pointed out by the FunWithSubtitles). He zig-zags between cheerful, remorseful and stoic.
* Multiple characters in Film/TheRoom, but Johnny most obviously. He (in)famously goes from a tirade about how his "future wife" has falsely accused him of domestic abuse to being happy to see his best friend.
* The titular character in [[Film/JulienDonkeyBoy Julien Donkey-Boy]], being a Paranoid Schizophrenic. His [[CloudCuckooLander eccentric]] Father (Played by Creator/WernerHerzog) also counts, both in a [[MoodWhiplash very]] [[NightmareFuel disturbing]] manner.
* Gary King in ''Film/TheWorldsEnd'' is this, quickly able to shift from sad and regretful, to serious, to excited and manic (his most common phase). [[spoiler: This is an early hint that all is not right in his head, and he uses his tendencies to help mask some of his deceptions from his friends.]]
[[/folder]]

[[folder:{{Literature}}]]
* Vlad Tepes in ''Literature/CountAndCountess'', usually to scary degrees.
* Tonker in ''[[Literature/{{Discworld}} Monstrous Regiment]]'' has only two moods: calm and berserk. The description used in the book is "has no middle gears."
* ''PeterPan'': This is Tinker Bell's original characterization. J.M. Barrie explains that fairies are 'so small they only have room for one feeling at a time.'
-->"Now, Tinker Bell was not all bad. At least, she was not all bad all the time."
** Hell, Peter's like this at least as much. Having been raised by fairies may have something to do with it.
* Less than halfway through the first novel, it's easy to see where theories of ''SherlockHolmes'' being bipolar come from.
* Edward Cullen of ''{{Twilight}}'' fame is a rather offputting example. He's portrayed as a [[TroubledButCute tortured, yet romantic]] gentleman who has the utmost devotion to Bella...but only when she's [[{{Extreme Doormat}} submissive]]. However, when she puts up even the slightest resistance or actually voices complaints, he quickly goes from a "sensitive" boyfriend to a frothing, rageful lunatic bent on putting her in her place. In addition to his [[{{Manipulative Bastard}} manipulative tendencies]], it is because of this that he serves as the perfect candidate for a walking PSA and redflag archive on DomesticAbuse.
* [[Literature/RevengeOfTheSith Anakin Skywalker]] isn't too different. His frustrations with the war, the Jedi, what he feels is a lack of respect from said Jedi, and his fears about Padmé's prophesised death mean conversations with him are a veritable minefield. Even Padmé herself isn't safe as the story goes on. Just mentioning she's been talking to a group of senators who aren't happy about the way the war is going is enough to get Anakin to act increasingly hostile. And that's before his FaceHeelTurn.
[[/folder]]

[[folder:LiveActionTV]]
* Dick from ''ThirdRockFromTheSun'': "I find you pompous, judgemental, and completely self-absorbed. Would you be my friend?"
** Not really an example; that was more Dick relating to those qualities because he's the exact same way.
* The wife of the man with the bazooka round in his chest in the bomb squad episode of ''GraysAnatomy''. She goes from uncontrollable screaming to uncontrollable tears to uncontrollable rage and then back to uncontrollable tears.
* Kevin the Teenager from ''Series/HarryEnfieldAndChums'' is a nightmarish example.
* ''MuppetsTonight'' director Nigel suffers from this, going from mellow to hysterical and back again at the drop of a hat. Though working with TheMuppets can have that affect on people.
* ''Series/{{Sherlock}}'s'' Jim Moriarty has, to say the least, a habit of doing this. "[[spoiler:SORRY BOYS! I'M SOOOOOO CHANGEABLE!]]"
* Tyres from ''{{Spaced}}'' does this frequently, with the camera angle often changing with his mood. [[JustifiedTrope Explained]] as a long-term side-effect of taking waaaaaaaaay too much ecstasy.
* ''Series/TheCaesars'' depicts [[TheCaligula Caligula]] as one of these; Caligula even says that he uses this to his advantage so that people do not know whether a given act of flattery will please him or anger him, thereby keeping them afraid of him.
* Cat in ''{{Victorious}}'' can go from happy to sad in under 4 sentences.
* A pregnancy example from ''Series/TheNanny.'' The combination of her pregnancy and her son moving away to college left Fran's emotions all over the place, pinballing around in seconds.
--> '''Niles:''' I thought tonight for a celebratory dinner, I would make salmon.
--> '''Fran:''' ''[Morose]'' Oh, no, those poor little salmons. They spend their whole life swimming upstream just to be poached for dinner?
--> '''Niles:''' I was going to barbecue.
--> '''Fran:''' ''[Chipper]'' Ooh, mesquite? With a teriyaki glaze? That would be perfect for Brighton's celebratory dinner. ''[Crying]'' my baby's leaving. ''[Angry]'' Who put their finger in the cake!?
--> '''Everyone else:''' ''[Slightly Confused]'' You did.
--> '''Fran:''' [[HypocriticalHumor Oh, well, aren't we a bunch of moody musketeers?]]
[[/folder]]

[[folder:Music]]
* RelientK: Whoever the song "Mood Rings" was about: "First she's Jekyll and then she's Hyde... at least she makes a lovely pair", indeed.
[[/folder]]

[[folder:TabletopGames]]
* Malfeas in ''{{Exalted}}'' is known to be bipolar on a [[MalevolentArchitecture huge scale]], but the real MoodSwinger among the Yozis is Kimbery, whose affections change like the tides - as soon as she's disappointed by you at all, she goes [[MyBelovedSmother lovelovelovelovelove]][[ThePowerOfHate SOMUCHHATE]]. Being in the second category is a death sentence; the first, a death sentence suspended until you inevitably enter category two.
* One of possible monsters in ''[[TabletopGame/{{Munchkin}} Munchkin Card Game]]'' is a "bipolar bear" - he will attack you furiously or run away, depending on its current mood.
[[/folder]]

[[folder:Theatre]]
* Lucy from ''Theatre/{{Thirteen}}'' has this dialogue with her boyfriend:
-->'''Lucy:''' ...And don't forget to change your facebook status to in a relationship. [[ClingyJealousGirl That way our profiles will be linked together like little love handcuffs]].\\
'''Brett:''' (To Cassie, who is walking by) Oh hi Cassie.\\
'''Lucy:''' Are you '''''flirting''''' with her?!\\
'''Brett:''' No, I was just saying Hi.\\
'''Lucy:''' So you're saying [[HollywoodPudgy I'm fat]]?\\
'''Brett:''' No.\\
'''Lucy:''' Well, you never say anything about how amazing I look anymore.\\
'''Brett:''' Lucy, you are driving me crazy.\\
'''Lucy:''' See? Now that was sweet. And sweet makes me sweet. Got it?\\
'''Brett:''' No.
[[/folder]]

[[folder:VideoGames]]
* The ''VideoGame/DanceDanceRevolution'' announcer, or at least the one from ''DDR Hottest Party''. He lavishes praise on you when you're doing well or even just ''okay'', but the second your dance meter falls into the red he'll angrily demand that you stop sucking. Also, when you idle on the song menu he demonstrates all the patience of a spoiled six-year-old ("'''''Bo-ring!'''''").
* Anders of ''VideoGame/DragonAgeII'' is stated in the Codex to suffer from manic and depressive phases as of Act III, due to the SanitySlippage caused by his DemonicPossession. His dialogue throughout the game tends to reflect this, ranging from calm and caring, to snarky, to obsessively focused on his goals, to self-righteously grandiose, to self-loathing and miserable, to downright psycho, with alarming speed.
* Due to programming, Cole Phelps from ''LANoire''. During interrogations, he'll typically ask a calm, polite question, and then if you select "Doubt" or "Lie", abruptly start screaming obscenities at the suspect, then return to normal for the next question.
* ''VideoGame/{{Persona 3}}'': While not as extreme as some of the others on the list, Yukari Takeba frequently goes through random moodswings through the course of the game. [[spoiler:Said mood swings get worse in [[PlayableEpilogue The Answer]] thanks to her grieving over the main character's death]].
** Perfectly understandable too, given the fact that, before the events of the game, she was (for the most part) a normal teenager.
* Silver from ''Franchise/SonicTheHedgehog''. When the player sees him, he's usually either moping around or being in-your-face and energetic. Given the pervasiveness and length of time between some of these episodes, it's possible that he's actually bipolar.
* Naoto's Shadow is this in ''VideoGame/{{Persona 4}}'', alternating between a MadScientist giving the real Naoto a TheReasonYouSuckSpeech and a FragileFlower bawling their eyes out.
* Cyrus of ''VideoGame/PokemonDiamondAndPearl'' is revealed in ''Platinum'' to be suppressing his uncontrollable moods, which he believes to be caused by [[StrawNihilist the inherently flawed nature of human spirit]]. It's suggested by his former neighbors that he [[BrokenAce snapped under pressure as a child]] and [[ThereAreNoTherapists never quite got the help he needed]].
** N of ''VideoGame/PokemonBlackAndWhite'' is mentioned by the creators to be moody, though it's hard to tell (and plenty justified) given [[AbusiveParents everything]] [[RaisedByWolves else]] [[TykeBomb that's]] [[HumansAreBastards wrong]] [[BlackAndWhiteMorality with]] [[ManChild him]].
* Wigglytuff in ''VideoGame/PokemonMysteryDungeonExplorers'' has this reputation (along with HairTriggerTemper), though at first it seems like its an InformedAttribute. [[FailureIsTheOnlyOption After you fail to bring back a Perfect Apple however]], he ''literally'' almost blows up the guild. Besides that, the aftermath of his CurbStompBattle with Team Skull supports this.
* In ''VideoGame/{{Psychonauts}}'', you delve into the brain of a former actress to control her mood swings. Her mind is represented by a stage where can change the atmosphere from cheery to depressing with a switch.
* ''SoulSeries'': Tira is either bloodthirsty-cheerful or bloodthirsty-angry. She can change semi-randomly during a fight.
** In her second appearance this [[{{Flanderization}} escalated]] from Bipolar, to actual split personalities and her fighting style changes depending the current mood/personality.
* Arguably all characters in the Galactic Adventures expansion for ''{{SPORE}}'', as players are only given 5 emotions to work with (happy, sad, angry, scared, and neutral which is just a different version of happy) when making dialogue portions for their user-created missions, and they're all expressed in the most exaggerated way possible without and transitions between them. This also makes certain character types such as the DeadpanSnarker and TheStoic very difficult to portray believably.
* This is the main gimmick of ''VideoGame/SuperPrincessPeach'': the heroine has four different moods that must be used in various ways. It didn't take long for people to mock the UnfortunateImplications of this.
* The Happy Mask Salesman in ''VideoGame/TheLegendOfZeldaMajorasMask''. There are literally no physical transitions between his extreme emotions.
* [[TroyBaker Troy Baker's]] [[SelfDemonstrating/TheJoker Joker]] veers into this in ''VideoGame/BatmanArkhamOrigins'': he can go from cracking jokes to his underlings, to [[DestinationDefenestration shoving a guy out of a window]], to raving about how much he loves the fruitcake.
* Madison Li of ''Videogame/{{Fallout 3}}'' has a habit of changing her tone from hostile and antagonistic to calm within the same sentence.
* Aerie in ''VideoGame/BaldursGate II'' wavers more or less arbitrarily between "scarred but functional" and "if I can't fly I might as well just kill myself".
[[/folder]]

[[folder:Visual Novels]]
* Arcueid from ''{{Tsukihime}}''. Nothing too drastic though, unless you make her really angry.
[[/folder]]

[[folder:Webcomics]]
* [[BigBad Zenith]] in WebComic/CommanderKitty is prone to wild mood swings. [[http://www.commanderkitty.com/2010/07/04/nothing-like-a-good-rant/ Watch her go from indignant ranting to happily discussing where to hide her goons]], [[http://www.commanderkitty.com/2011/08/28/process-of-elimination/ or from total despair to omnicidal rage]]!
* In ''[[DanAndMabsFurryAdventures DMFA]]'', for the 'cubi [[http://missmab.com/Comics/Vol_1207.php it's a racial trait linked to their emotion based powers.]] A 'cubi is both mercurial and feels emotions more strongly than any other creature or being.
* The fairy Red from ''Webcomic/GunnerkriggCourt'' veers between smarmy affection, despondency, and rage. If anything, she gets worse after she [[{{Metamorphosis}} becomes a human]]. ([[TheMindIsAPlaythingOfTheBody Maybe it's the hormones]].)
** Zimmy is similar, though her personality is a bit more subdued. (Read: not psychotic.) Her mood swings revolve around her friend Gamma. An in-depth analysis of Zimmy's issues on the matter would make this page about twice as long, but the short version is this: Gamma acts as a grounding wire for the bulk of Zimmy's RealityWarper powers, which she can't control, and thus keeps Zimmy's mind mostly at peace. Zimmy is nonetheless aware that she's not a lot of fun to be around, and is terrified that if Gamma thought she had any other friends, she'd spend her time with them instead of Zimmy; between this fear, and the power Gamma can't drain away, her overall reaction to the world is erratic and designed to keep people at arms' length by whatever means necessary.
* Sollux of ''Webcomic/{{Homestuck}}'' has this problem, and tends to lapse in and out of HeroicSelfDeprecation repeatedly. It's part of his overall theme of duality and bifurcation, as Gemini in the Trolls' WesternZodiac motif.
** [[spoiler: Sollux's ancestor-descendant Mituna]] also turns the intensity of Sollux's mood swings up a few notches, swinging erratically between being a raving, [[ClusterFBomb foulmouthed]] JerkAss and a cowed, apologetic ExtremeDoormat. [[spoiler: It may not have always been so bad, seeing as he suffered a HeroicRROD that severely crippled his mind before his introduction]].
* Jean Poule in ''TheInexplicableAdventuresOfBob''.
* ''Webcomic/MenageA3'' has Kiley Shefford, a trainee psychotherapist who sometimes seems like she could do with some therapy herself.[[note]]Actually, she admits as much, and has been getting both actual therapy and something that she ''calls'' therapy, though not of a conventional kind. [[IntimatePsychotherapy Hint; this is a sex comedy.]][[/note]] Her most dangerous flaw may be an excessive but fragile confidence in her own abilities. She [[http://www.ma3comic.com/strips-ma3/all_your_comics jumps from cynical sarcasm to wild enthusiasm,]] [[http://www.ma3comic.com/strips-ma3/or_whatever from tearful panic to jumping someone,]] from "I'm such a good therapist" (strip #515, October 20th 2011, NSFW) to [[http://www.ma3comic.com/strips-ma3/the_worst_therapist_in_the_world "I'm the worst therapist in the world",]] from [[http://www.ma3comic.com/strips-ma3/okay-sized ecstasy to tears,]] or from [[http://www.ma3comic.com/strips-ma3/calm_down anger to sobbing,]] with minimal provocation.
[[/folder]]

[[folder:WebOriginal]]
* The 20 Questions-playing Website/{{Akinator}} can switch between smug satisfaction and red-hot rage between one question and the next, if what he thought was a perfect guess is thrown off by an answer that doesn't fit the bill.
* WebVideo/TheNostalgiaCritic. All it takes is one bad move from a film and he'll go apeshit. Case in point?
-->'''Critic:''' A BAT CREDIT CARD???????!!! I'LL KILL ALL OF YOU!
-->*3 hours later*
-->'''Critic:''' Sorry. I just get a little crazy when I see a BAT CREDIT CAR-!!!
-->*12 hours later*
-->'''Critic:''' ...RAPE MY CHILDHOOD YOU-
* PlayedForDrama in WebVideo/DemoReel with Tom Collins. During a phone call message to Donnie, he goes from jovially commenting that SWAG is pretty awesome, to full-blown-stalker threats telling Donnie to not even think about ignoring him.
* [[http://www.youtube.com/watch?v=LfaRPev8cbA Terry, the Bi Bi-polar Polar Bear]].
-->'''[[CampGay Terry]]:''' I just want you all to know that I don't care if you're a boy penguin or a girl penguin, I just... Aw, heck, I'm just gonna come right out and say it: I love you all to pieces!\\
'''Penguin:''' Oh, thanks Terry. We all love yo--\\
'''Terry:''' '''GO TO HELL!!''' *Runs off crying*
[[/folder]]

[[folder:WesternAnimation]]
* ''AaahhRealMonsters'' had Ickis, the UglyCute lead with '''serious''' issues. He could go from [[ThisIsNoTimeToPanic nervous stammering]] to [[{{Keet}} bouncing off the walls]] to [[{{Pride}} grossly inflated overconfidence]] and [[OhCrap back]] in minutes. And that doesn't even get into his bouts of [[WideEyedIdealist wide-eyed idealism]] and [[NaiveEverygirl naivete]]...
* ''WesternAnimation/AvatarTheLastAirbender'': Katara is pretty much this trope to a T. Justified given she's a teenage girl who's had a lot to deal with over the last few years.
** Also Prince Zuko. One minute, he's calm, focused, and disciplined. The next, exploding in a flurry of grunts, growls, and fireballs. Even as a good guy, his mood doesn't improve much until the end. This is why he cannot use Lightning Bending, which requires absolute control over one's emotions.
* Lunch Lady from ''WesternAnimation/DannyPhantom'' who switches from kind, grandmotherly figure to full-blown "I'll '''KEEL''' you" mode at the drop of a hat. Her [[spoiler:alternate future daughter]] picked up the habit as well.
* The titular InvaderZim.
* Heloise from ''{{Jimmy Two-Shoes}}'' tends to switch from AxCrazy EnfantTerrible mode, to sweet and innocent mode, to DeadpanSnarker mode, to flirtatiously lovable mode (around Jimmy), to [[HairTriggerTemper pissed off mode]] and back again.
* Doctor Drakken from ''WesternAnimation/KimPossible'' seems to go from mood to mood like an acrobat does on swings.
** In the episode "Emotion Sickness", Kim and Shego become Mood Swingers thanks to the Moodulators attached to them. Ron and Drakken end up being on the receiving end of all of their emotions.
* Hexadecimal in ''ReBoot'' has her mood swings lampshaded - her face consists entirely of a theater mask, and she has to manually wave her hand across it to change its exaggerated expression.
* ''WesternAnimation/{{Superjail}}'' - The Warden.
--> (sees dead bunny) "You... sick... bastard." (squishes dead bunny, merrily sends the bunny's kidnapper off in a rocket ship, and holds dead bunny up) "Heeey, little guy! Underneath all that precious fur..." (cuddles dead bunny mournfully) "All scared and all alone..." (pets dead bunny contentedly, starts singing) "If only~ they knew~ what it was like~ to be~ yyyyoooOOOOUUUU!" (rips dead bunny's skin off and gleefully wears it as a hat) "Jared, I want one of these for each and every inmate, not a moment to spare!"
* Lola Bunny from ''TheLooneyTunesShow'' has a tendency to have little control over her emotions, one moments she can be crying her eyes out and the next she's laughing her ass off. Being a CloudCuckoolander, it could be attributed to her never being entirely sure what's going on around her.
* Ren from ''TheRenAndStimpyShow''.
* Made fun of in one episode of ''WesternAnimation/TheSimpsons''. Homer takes sleeping pills to [[ExactlyWhatItSaysOnTheTin sleep well through the night]] and Lisa reads off the side-effects, one which is Mood Swings. Cue Homer repeatedly saying "Mood Swings" in various [[ExactlyWhatItSaysOnTheTin moods]].
* Blitzwing the Triple-Changer from ''WesternAnimation/TransformersAnimated'', who switches rapidly between three personalities/moods: [[AnIcePerson Icy]] ([[TheStoic stoick]] and calculating), [[PlayingWithFire Hothead]] (enraged and HotBlooded), and [[GigglingVillain Random]] (who is... well, [[{{Cloudcuckoolander}} Random]]).
** In [[WesternAnimation/TheTransformers the original series]] [[AxCrazy Galvatron]] would switch moods at a drop of a hat. His moods seemed either insanely gleeful, terrified, sarcastic, calm or enraged. His moodiness is a symptom of his damaged metaprocessor (along with irrational behaviour).
* Peg from ''WesternAnimation/GoofTroop'' can switch from being sweet and happy to terrifyingly angry in the same sentence, and effortlessly move back and forth between them. This usually occurs because she's addressing two parties at once, one she has a beef with and one she doesn't.
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[[folder:RealLife]]
* Rapid cycling bipolar disorder (in which the characteristic mood swings take place in periods of days or even hours, rather than weeks as is more typical) somewhat resembles this trope, and as noted above most fictional characters with bipolar disorder are depicted this way despite it being comparatively rare.
* One of the key symptoms of Borderline Personality Disorder are rapid mood swings that can happen within hours. [[note]]As stated in the DSM-IV manual : "''6. Affective instability due to a marked reactivity of mood (e.g., intense episodic dysphoria, irritability or anxiety usually lasting a few hours and only rarely more than a few days)''".[[/note]] This trope is so much a core indicator of that disorder, in fact, that some propose to change its name to "Emotional (dys)regulation disorder" because the term "Borderline" is outdated and carries too much social stigma.
** To be clear, the key difference between BPD and bipolar disorder is that mood swings in BPD are ''always'' a response to external stimuli (even if it is something as trivial as your pen being out of ink) while mood swings in bipolar disorder are spontaneous.
* Some people with PTSD have mood swings as part of the hyperarousal aspect of the disorder.
* [[NamesToRunAwayFromReallyFast Ivan the Terrible]] had mood swings as a side effect of the quicksilver he used to treat his pain, one bipolar episode had him beat his son to death in a fit of rage. He reacted with devestating sadness.
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